Hurricane crippled my off-grid system; asking for input what might have happened

Fenachrone

My off-grid 24-volt system consisting of six photovoltaic panels, an Outback MX-60 charge controller, Outback FX2424 inverter, Outback Mate, and four AGM batteries had been operating normally through the summer in this vacation cottage. This installation dates back to 2006, so that is the age of the Outback gear. Yet, never a hiccup. Only change I ever made was going to the AGM batteries almost two years ago, from flooded lead acid.

Hurricane Ian ripped across this island and tore four of my panels from their ground mount and broke their electrical connection to the combiner box.  We were not able to get in to survey the situation for three weeks, due to trees being down. The system had been left on from the summer but worked normally as reported by guests in September. 

Upon arrival, my Trimetric indicated b.low, and voltage .09.9, and inverter showed "low".   I figured the batteries had drained with the fridge on and the drain from the inverter itself.  I switched the inverter off, then back on.  Upon doing so, it, and the MX-60 went blank.

I've hooked up my generator, which I've routinely used for low sun periods. Typically, once I start it up, it will indicate on the Mate that it's beginning to draw current to charge the batteries.  With the generator running I did not get any status reading on my charge controller or Mate whatsoever -- completely blank. I was able to switch to "bypass" mode so we were able to run the house off the generator.

I've managed to re-connect some panels, but am still getting no response from the charge controller.

I'm far from knowledgeable about these things, but am guessing my AGM batteries have been damaged by being drained and not charged back in enough time? Would that account for the fact that I can't seem to get any charge in them from the generator.

Any thoughts on the possible cause or other impressions, are greatly appreciated.

littleharbor2

I would shut down panels, then battery connection, then try and charge the batteries with the generator and whatever else you need, ie an Iota charger , automotive charger or whatever means you have to get the batteries charged up .  once you have the voltage in a usable range see if you can boot up the charge controller. Once booted up then reconnect the PV.
 Most likely the Outback wont restart till it sees proper voltage.

Dave Angelini

You have a voltmeter? Use an external automotive charger to see if the batteries will take a charge. You will need to disconnect/ reconnect them to do this.  They probably will not charge but cross your fingers anyway!  Good Luck!

BB.

More or less, you need at least 9 VDC to "boot" "most" charge controllers. And you probably need >18 VDC on the battery bus to have the charge controller "recognize" this as a 24 VDC battery bank.

And remember that 21.0 VDC is "dead" as far as Lead Acid/AGM batteries are concerned.

If all you have is a 12 volt  battery charger... Clip onto each 12 volt "bank" and get some AH into them to where each 12 volt bank is >10.5 volts (and holds it, once the charger is removed). Depending on the rating of the charger and the battery bank--This may take, at least, a few hours of charging per bank to get them to a stable, not dead, state.

Otherwise, probably would not be a bad time to start looking for a replacement battery bank. Taking Lead Acid batteries to "dead" usually ends up with, at best, an unreliable battery bank (may simply "go dead" a few days or weeks from now for no apparent reason).

If you can get the existing bank "alive now", you can at least check out the rest of the hardware and see that the rest is working--If you have other failures (inverter, charge controller, etc.), you may need to revisit the whole system and figure out where to go next.

-Bill

Marc Kurth

Some AGM batteries need to be hit hard during the recovery process, others need a gentle touch.

In general, AGM batteries by Vision, VMAX, Mighty Max, UPG, etc. need to be gently coaxed back to life by avoiding anything over about 10 amps per 100 amps of battery capacity.

East Penn (Delka, MK, and their multitude of OEM brands), will respond better to 15v for 3-5 hours, with a current limit of 20 amps per 100.

Fullriver and Concorde will recover better with a whole different approach using 15.5v to 18v under specific controlled temperature/time and current limits.

What do you have?

Marc

Dave Angelini

Some maybe, but most Lead bats that I have seen are goners when they are old, and have taken this abuse for a long period of time as stated.

I live in a gaming state now, really low odds for success on this one. Time is the enemy here.

Fenachrone

I appreciate all these responses.   I went ahead and got an 8A auto battery charger and began charging one bank of two batteries together in series (to get 12v), then the other.  I did two rounds of charging, several hours each.   The first round with the initial two batteries resulted in the battery charger indicating “bad battery” and the charger then shut off.  In the second round with that set, there was no “bad battery” message or shut-off.  The second set of batteries charged in both rounds without a “bad battery” message.  I forget the exact readings with my voltmeter (couldn’t see well in my crawl space, but maybe around 14 volts) but I do remember the “bad battery” bank read lower.

With the inverter still off and with the day being sunny, I switched on an undamaged string of three panels.  Because the angle of the sun is low here this time of year, and with an unmovable array, we only got around 400 watts output.  The charge controller indicated 16 volts and inching upwards, so it appeared the batteries were charging.  We had to leave a few hours and when we got back, noticed we were at around 21 volts.

 I reconnected everything, switched the inverter on and it came alive, albeit with low battery indicators.  I started the generator and the system began “buying” power.   I watched the voltage go up to around 25 volts in a short time.  However, soon the GFCI on my generator cut out; it’s a Yamaha EF2800i, not the most beefy generator obviously, and prone to the GFCI cutting out in general with seemingly moderate loads.

I reset the GFCI several times and the same thing happened: up to about 25 volts, then after a few minutes, the GFCI cuts out, and then we're back to 21 volts.

So were these batteries on the way back, but the generator couldn’t do the job?  Or if this a sign of battery failure, i.e., the “bad battery” bank?   We have sunny days coming up.  Could the panels charging the next couple days kind of nudge these batteries upwards? And can it be that easy to kill AGMs?

One writer asked what brand these AGM’s are.  I remember them being some generic brand, obtained by my electrician, but nothing I was familiar with.  They come with a 2-year warranty. 

Marc Kurth

 

Dave Angelini said:

Some maybe, but most Lead bats that I have seen are goners when they are old, and have taken this abuse for a long period of time as stated.

I live in a gaming state now, really low odds for success on this one. Time is the enemy here.

Yes, sir, I agree. But these batteries are reported to be "almost 2 years old."  I have brought a LOT of 2.5v (6v batteries) back to 80%-85% capacity and gained my customer another season or three. It rarely works if they have been sitting below about 1.6v per cell for a couple of months, but 2-4 weeks is a different story with a quality AGM.

littleharbor2

Good to hear your system seems to be working. Your batteries, not so much. Might be time to seek out another battery chemistry.

Dave Angelini

Certainly start lining up a replacement as these times of supply chain issues can be a PITA. In Florida, your local battery guys are probably super strained.

 I would call the store here and see what they can supply you with. Be careful of using lithium with your system if it is used for rentals. The old electronics like you have often do not back-up memory well and do not have the charge choices for lithium. Might open up a new can of worms unless you spend the time and due diligence.

If you do get the old batteries going, there is a very high chance they have lost alot of capacity! Another reason to replace with rental people being there.

Fenachrone

Points well taken.   Right now I have the batteries at 23v with solar charging, but that was also the case yesterday.   It falls right off when the sun goes down.  I have a sense these batteries are mediocre, notwithstanding the harm due to them being drained and not recharged again quickly.  I might be able to get a warranty replacement or replacement via my insurance coverage. 

Dave Angelini

The battery warranty road is going to waste more time but who knows.... My experience is they will know the batteries were abused and deny your claim. And that is a good company. If you can't read the name on the battery......

Marc Kurth

Dave Angelini said:

The battery warranty road is going to waste more time but who knows.... My experience is they will know the batteries were abused and deny your claim. And that is a good company. If you can't read the name on the battery......

Solid, accurate advice.

JRHill

Lead battery warranties are just another reason I moved to SimpliPhi. On my last set of Trojan L16RE-B I got warranty honked when two in the bank had one cell each fail. The dealer 'tested' them and said I boiled them dry. Total BS. Regular checks, kept 'em full AND records including the SGs. At least the Phis have a BMS which provides some protections but also a memory. The Mfgr can use the memory to their advantage but not necessarily mine and, darn, it is not readable by anyone but them. Hopefully I'll not find out for a long, long time. I'll not use lead for anything but a starting battery again if I can help it. I can't be more impressed with the Phis' performance but they're only two years old.

Mr. Fenachrone, you can guess my recommendation if you have to update your bank.  But your older OB hardware could be a limiting factor for low voltage cut-off and some other tuning/usage considerations.

Fenachrone

We've gotten the bank up to 25v with solar charging, and that with our fixed panel rack not optimally oriented for the low arc of the sun

in this northern region.   That's not to say these batteries aren't compromised - they don't seem to hold charge that well - but even this performance wouldn't have been expected a few days ago.

In about 10 days we'll close this house for the season.  I would say we can limp through.  I'm hesitant to commission a new set of

batteries then leave them until June, albeit with charging left on. 

Some clarity on the brand of these batteries: I now remember the vendor saying these were Rolls/Surrette, though they are not labelled as such. I have no way of verifying it, and I suppose it's immaterial at this point.

littleharbor2

Do they look like these? 

Fenachrone

More like this.   

Dave Angelini

If they look and are in fact Rolls batteries you have a quality product.  Your problem is as Marc speced out here, is the charge current and the right voltage. If you can't do that soon they will be destroyed. They probably are already are.

 In my business my clients do not have time for this as they live off their battery systems. It is the cost of living in a beautiful place.

I use Rolls alot in the flooded type. My guy is Steve Higgins ⋅ Technical Services Manager

t +1.902.597.4020  m +1.206.790.5840

littleharbor2

Fenachrone said:

More like this.   

So Rolls AGM type? smooth top, no filler caps?

Dave Angelini

If you do call Steve at Rolls, and he is the best at his product, you will need serial numbers and proof of purchase just to start. 
 Good Luck !

Fenachrone

That's right, littleharbour2, the smooth top with no filler caps.  What's curious to me is that, to the best of my knowledge, Rolls batteries are made in Springhill, Nova Scotia.  Mine are made in Vietnam.  Maybe Rolls has subbed out some manufacturing there?  Again, though, I have no way of knowing if these are made by Rolls in any respect.

I have great respect for Rolls.  Before going to the AGMs, I had their S460 FLA batteries.  They lasted 14 years, well beyond their 7 yr. warranty, and might have gone further if this wasn't a seasonal home and I lived locally whereas I could have managed them better.

But my replacements will be their AGMs.  A little outfit in New Brunswick, Cabin Depot, has them.

Thanks Dave A, for the reference to Steve, the technical services manager at Rolls.  I've spoken to them with questions a couple times and they've been more than generous with assistance.

Right now, we'll get through the next week OK before heading back home to Massachusetts.  The pattern here is that with cloudy days, I run the genny a bit in the morning, then we're fine until nighttime.  The batteries fall fast at night even when getting up to 25-26v in good charging conditions, and we don't even have heavy loads in his house.

 

Dave Angelini

Good Luck! You are right that Rolls does not make the AGM or their LFP battery. Both are from good companies though. This all can change with time these days. Weird times.....

Marc Kurth

Fullriver supplied their L16 6v AGMs for several battery manufacturers for several years.